Ryan Hunter-Reay took his second IndyCar win in as many weeks with his victory in an unusual Iowa Corn 250 at Iowa Speedway on Saturday night.

The Andretti Autosport driver passed Target Chip Ganassi Racing's Scott Dixon for the lead with just 14 laps to go, and faced the prospect of a battle to the finish with teammate Marco Andretti before Dragon Racing's Katherine Legge spun and brought out a caution with four laps to go, leaving the race to finish under yellow.

"That was very challenging," said Hunter-Reay. "We were sliding around a little bit more today. I have to thank Marco. They came here and tested. Marco put the setup on the car. When we came here, we tweaked it just a little. From there, we basically raced with what he tested. 

"Marco and I raced really hard out there, really clean. It's great to have a teammate like that and we're just so happy to be in Victory Lane twice in a row."

"The car came alive in the second stint," said Andretti, who won this race last year. "I think we, in hindsight, could have taken another turn of the front wing and been really hard to beat at the end, but we kept the car how it is and I kind of ran out of tools at the end and had a lot of understeer. Great team effort, definitely a statement from Andretti Autosport and congrats to Ryan."

Tony Kanaan (KV Racing Technology) also managed to pass a fading Dixon late in the race to claim the final spot on the podium. Dixon held on for fourth ahead of Schmidt Hamilton's Simon Pagenaud, who did a superb job to climb through the field from the back of the grid.

Thunderstorms before the start forced a one-hour delay while the track was dried out, and the green flag had not even waved before the race threw its first curveball of the evening when polesitter Dario Franchitti (Ganassi) pulled off the track with a blown engine during a warm-up lap.

Franchitti's misfortune set the tone for an evening of high attrition, which was reflected in the six caution periods that punctuated the race. Eleven cars failed to make it to the finish including championship leader Will Power, who turned in on an unsighted EJ Viso (KV) and put both himself and the Venezuelan into the wall.

Power's Penske teammate Ryan Briscoe was another casualty later on when he fell victim to a challenge from Sarah Fisher Hartman's Josef Newgarden while leading. The consequent impact spelled the end of the race for both drivers.

Other significant retirements including championship contender James Hinchcliffe, who was caught out by a combination of cold tires and dirty air and spun his Andretti Dallara-Chevrolet into the barriers.

Results - 250 laps:

Pos  Driver               Team/Car                     Time/Gap
 1.  Ryan Hunter-Reay     Andretti DW12-Chevy     1h43m39.3031s
 2.  Marco Andretti       Andretti DW12-Chevy         + 0.1103s
 3.  Tony Kanaan          KV DW12-Chevy               + 2.7245s
 4.  Scott Dixon          Ganassi DW12-Honda          + 3.0075s
 5.  Simon Pagenaud       Schmidt DW12-Honda          + 3.8468s
 6.  Helio Castroneves    Penske DW12-Chevy           + 5.3061s
 7.  Rubens Barrichello   KV DW12-Chevy               + 5.9890s
 8.  Ed Carpenter         Carpenter DW12-Chevy        + 6.9856s
 9.  Graham Rahal         Ganassi DW12-Honda          + 7.1607s
10.  Justin Wilson        Coyne DW12-Honda              + 1 lap
11.  Charlie Kimball      Ganassi DW12-Honda           + 2 laps
12.  Takuma Sato          Rahal DW12-Honda             + 3 laps
13.  James Jakes          Coyne DW12-Honda             + 5 laps
14.  Simona de Silvestro  HVM DW12-Lotus               + 6 laps

Retirements:

     Katherine Legge      Dragon DW12-Chevy            243 laps
     Alex Tagliani        Herta DW12-Honda             207 laps
     James Hinchcliffe    Andretti DW12-Chevy          195 laps
     Ryan Briscoe         Penske DW12-Chevy            178 laps
     Josef Newgarden      Fisher DW12-Honda            178 laps
     Mike Conway          Foyt DW12-Honda              123 laps
     Oriol Servia         Panther/DRR DW12-Chevy        98 laps
     JR Hildebrand        Panther DW12-Chevy            95 laps
     Will Power           Penske DW12-Chevy             67 laps
     EJ Viso              KV DW12-Chevy                 67 laps
     Dario Franchitti     Ganassi DW12-Honda             0 laps